The present disclosure relates to the subject matter contained in Japanese Patent Application No. 2002-171011 filed on Jun. 12, 2002, which is incorporated herein by reference in its entirety.
1. Field of the Invention
The present invention relates to a two-piece clip which is configured by a grommet and a pin, and which is used for coupling two panels with each other or the like.
2. Description of the Related Art
Usually, a two-piece clip is configured by: a grommet having elastic leg portions which are formed by dividing into plural parts a portion elongating from an annular flange; and a pin having a shaft which is to be inserted between the elastic leg portions through a center hole of the flange, whereby the elastic leg portions are radially expanded.
Such two-piece clips are widely used in various fields such as fixation of automobile parts. For example, a pair of panels which are to be coupled are overlaid on each other so that their mounting holes coincide with each other, and the pin is previously inserted into the grommet by a degree at which the legs are not opened. Under this state, the legs of the grommet are inserted into the coincident mounting holes to make the flange of the grommet butt against one of the panels. When the pin is pressingly inserted under this state, the legs of the grommet are expanded by the shaft of the pin, and the pair of panels are clamped by the flange of the grommet and the legs to be coupled with each other.
A two-piece clip having such a configuration is proposed in JP-UM-A-6-51522. An engagement pawl which elongates in an inner radial direction and in an axial tip end direction are formed on an inner face of a shaft of a grommet so that a pin and the grommet take one of: a first coupling position where a shaft of the pin is inserted into the grommet shaft, the grommet shaft is not radially expanded by the pin shaft, and a flange of the pin separates from a flange of the grommet; a second coupling position where the pin shaft is inserted into the grommet shaft, the grommet shaft is radially expanded by the pin shaft, and the pin flange is in contact with the grommet flange; and a third coupling position where the pin shaft is pulled in the grommet shaft from the second coupling position under a state where the pin shaft is inserted into the grommet shaft but the pin flange separates from the grommet flange. Engagement grooves which are to receive the engagement pawl are formed in the pin shaft. The engagement groove which is to be engaged at the third coupling position with the engagement pawl is formed into a shape in which the tip end of the engagement pawl is restricted to the engagement groove so that the pin shaft is not further pulled out from the grommet shaft. The engagement pawl of the grommet shaft which is to be engaged at the third coupling position with the engagement groove is disposed at any level that is between a face of a to-be-mounted member through which the grommet shaft is passed, and the grommet flange.
In a conventional two-piece clip, under the state where a pin is inserted halfway into a grommet and legs of the grommet are not radially expanded, the pin and the grommet are usually inserted into mounting holes of to-be-mounted members while the heads of the pin and the grommet are nipped. However, it is difficult to nip the pin and the grommet by fingers because the length between a flange of the grommet and the head of the pin is short, thereby causing a problem in that the work of inserting the clip into mounting holes is hardly conducted. In the case where the hole of the front to-be-mounted member is positionally shifted from that of the rear to-be-mounted member, particularly, it is required to search the holes by changing the direction of the legs of the grommet while nipping the heads of the pin and the grommet. When it is difficult to nip the heads of the pin and the grommet, the workability of the mounting work tends to be extremely impaired.
By contrast, in the two-piece clip disclosed in JP-UM-A-6-51522, the head of the pin largely protrudes from the grommet under the state where the clip is temporarily assembled in the first coupling position. Therefore, the clip has an advantage that the head of the pin can be easily nipped when the clip is to be inserted into the mounting holes of the to-be-mounted members.
In the above two-piece clip, when, after the to-be-mounted members are coupled with each other by pressing the head of the pin, the to-be-mounted members must be uncoupled for any reason, the engagement between the legs of the grommet and the shaft of the pin is cancelled, the shaft of the pin is pulled out to radially contract the legs of the grommet, and under this state the legs of the grommet is pulled out from the mounting holes. In this case, there arises a problem in that the engagement pawl of the shaft of the grommet is broken and hence temporary locking at the first coupling position cannot be conducted when the pin is to be reused.
It is an object of the invention to provide a two-piece clip in which temporary locking can be conducted under the state where the head of a pin largely protrudes from a grommet, and in which, after the pin is pressingly inserted into the grommet to be coupled therewith, the pin can be pulled out to cancel the coupling, and the temporary locked state can be again set so that the clip can be reused.
A two-piece clip according to a first aspect of the invention includes a grommet and a pin. The grommet includes an annular flange defining a center hole and a plurality of elastic leg portions separately extending from the flange. The pin includes a shaft, a temporarily locking piece, and a locking protrusion. The shaft radially expands the elastic leg portions when the shaft is inserted among the elastic leg portions through the center hole. The temporarily locking piece extends from the shaft to protrude in an outer radial direction. The locking protrusion is formed on the shaft to be adjacent to the temporarily locking piece in a shaft tip end direction. The shaft and the temporarily locking piece define an opening therebetween so that the temporarily locking piece has a bridge shape. In a process of inserting the pin into the grommet, an inner peripheral edge of the flange is engaged between the temporarily locking piece and the locking protrusion in a state where the leg portions are not radially expanded, and the pin is temporarily locked to the grommet.
According to the invention, under the state where the pin is in mid-course of press insertion of the pin between the elastic leg portions and the legs are not radially expanded, the inner peripheral edge of the flange is engaged between the temporarily locking piece and the locking protrusion, and the pin is temporarily locked to the grommet. Therefore, the temporary locking can be conducted under the state where the head of the pin largely protrudes from the grommet, and the head of the pin can be easily nipped by fingers. In a case such as that where the front and rear to-be-mounted members are positionally shifted from each other and it is required to search a mounting hole of a rear to-be-mounted member after the clip is inserted into a mounting hole of a front to-be-mounted member, consequently, the work can be easily conducted.
When the to-be-mounted members are to be uncoupled after the to-be-mounted members are coupled with each other by pressing the pin to radially expand the legs of the grommet, the pin must be pulled out from the grommet to radially contract the legs. In this case, the axial ends of the temporarily locking piece are connected to the shaft of the pin so that the temporarily locking piece is formed into a bridge-like shape, and hence the temporarily locking piece is prevented from being broken. When the clip is to be reused, therefore, the pin is pulled back halfway from the grommet to cause the inner peripheral edge of the flange to be engaged between the temporarily locking piece and the locking protrusion, thereby enabling the pin to be again temporarily locked to the grommet.
Since the temporarily locking piece has a bridge-like shape as described above, the temporarily locking piece exhibits high elasticity against an external force in a radial direction. Therefore, the insertion resistance which is produced when the pin is pressed to couple to-be-mounted members can be reduced to a relatively small value, so that the work of pressing the pin is not hindered.
In addition to the first aspect of the invention, in a second aspect of the invention, a protrusion height of the locking protrusion is higher than that of the temporarily locking piece. The temporarily locking piece is more easily elastically deformed than the locking protrusion.
According to the invention, when the pin tries to slip off from the grommet under the state where the pin is inserted halfway into the grommet to be temporarily locked, the locking protrusion is firmly engaged with the inner peripheral edge of the grommet. Therefore, the pin is prevented from slipping off.
In addition to the first or second aspect of the invention, in a third aspect of the invention, the temporarily locking piece is two temporarily locking pieces. The temporarily locking pieces are formed at two positions, which are opposed to each other in a circumferential direction of the shaft.
According to the invention, molds for injection molding the bridge-like temporarily locking piece can be easily produced, and the pin can be stably held to the grommet by performing the temporarily locking at two places opposed in the circumferential direction.